Erecting means for gyroscopes



Nov. 3, 1942. H. G. HAMILTON 1 2,300,548

ERECTING ME-ANS FOR GYROSCOPES Filed Feb. ll, 1941 INVENTOR.

ATToRNEYs.

Patented Nov. 3, 1942 ERECTIN MEANS FOR GYROSCGPES Hugh G. Hamilton,Montclair, N. J.,v assignor to Bendix Aviation Corporation, Bendix, N.J., a

corporation of Delaware Application February 11, 1941, Serial No.378,433

(Cl. Z4-5) 4 Claims.

This invention relates to gyroscopic devices of ther type adapted forindicating the true vertical so as to provide an artificial horizon onmobile vehicles such, for example, as aircraft, and more particularly,to self-erecting means for such devices for maintaining the gyro spinaxis vertical.

In prior art devices such, for example, as represented by the UnitedStates patent to Robert Alkan 2,159,118 issued May 23, 1939, provisionwas made for erecting gyro-'verticals by the use of masses and/or ballsrotating and/or rolling about the gyro spin axis. These structures,however, reciuired the provision of circular tracks for guiding themasses and/or balls with the ensuing disadvantages that oftentimesbinding of the former with the latter would result. Further, upon theaccumulation of oil and dirt within the track, undue friction wasimposed upon the masses and/or balls, whereby the accuracy of theerecting mechanism was impaired and the dependability of the gyroreduced.

An object of the present invention, therefore,

-is to provide a gyro vertical or artiiicial horizon with a novelerecting mechanism, whereby the foregoing disadvantages will beovercome.

Another object of the invention is to provide a gyro vertical orartificial horizon having novel means for rapidly damping theoscillations or precession of the gyroscope about it.; position ofequilibrium.

than the speed of the gyro rotor, a container ro- Y tated by the frameabout vthe gyro spin axis, a

A further object of the invention is to provide l a novel gyro verticalor articial horizon in which disturbances thereof due to accelerationsproduced by turning of the aircraft upon which the instrument is mountedor due to other accelerations are materially reduced.

Another object of the invention is to provide a gyro vertical orarticial horizon with a novel and improved verecting mechanismcomprising a suitable container mounted for rotatable movement about thegyro spin axis, the container being provided with a globule of mercuryand dening a path for limited linear movement of the mercury thereinduring a deviation of the gyro spin axis from its normal positionwhereby moments are developed upon the gyro suspension to return thespin axis to normal.

A still further object of the invention is to provide in a gyro verticalor artificial horizon, novel means for maintaining the gyro spin axis ina normally vertical position comprising a frame rotatable about the gyrospin axis, driving means operated by the gyro for rotating the frameglobule of mercury contained within the container for limited movementtherein, and braking means connected to the frame and cooperating with axed part of the gyro assembly for variably braking the rotation of theframe to vary the speed thereof and of the container whereby the mercurytherein moves from one end of the container to the other, the brakingmeans including an escapement wheel anda non-isochronous anchorcooperating therewith to regulate the braking means and to produce aresisting couple to the rotation of the frame proportional to the speedof rotation of the container together with the mercury therein, thebraking means being rendered effective by the container and the mercuryupon deviation of the spin axis of the gyro rotor from the vertical-toproduce erecting forces upon the gyro suspension for returning the gyrospin axis back to the vertical position. A

The above and other objects and advantages of the invention will appearmore fully hereinafter from a consideration of the detailed description'which follows, taken together with the accompanying drawing wherein oneembodiment of the invention is illustrated. It is to be expresslyunderstood, however, that the drawing is for the purpose of illustrationand description only and is not designed as a definition of the limitsof the invention, reference being had for the latter purpose to theappended claims.

In vthe drawing, wherein like reference characters refer to like partsin both views,

Figure 1 is a top plan view of a gyro vertical embodying the presentinvention, with a top portion of the gyro casing removed, showingtheabout the spin axis at a speed substantially less novel erecting meansof the invention; and,

Figure 2 is a vertical section taken substantially along line 2-2 ofFigure 1.

The gyro vertical embodying the invention comprises a gyroscope having aVrotor mounted in a Cardan suspension for'spinning about a normallyvertical axis and for angular movement about two mutually perpendicularhorizontal axes at right angles to the spin axis, the rotor beingenclosed and journalled, in the present instance, in a casing carried ingimbals forming the Cardan suspension. The gyro rotor may be drivenelec# tically or in any other suitable and desired manner known in theart.

The novel means. for stabilizing the gyroscope and maintaining its spinaxis vertical in order that the gyroscope may serve as a gyro verticalor artificial horizon, comprises a globule of mercury molmtediol-limited linearmovement withinanenclosedcontainerwhichinturnismountedforrotationaboutthegyrorotorspinaxis. For this latter Pm there areprovided means inthefonnoi'aframeorcarriagemountedcoaxiallywiththegyzospinaxiscooperatingwith themercurycmixinertomtatethesameabout.

thegyrospinatis. Ithasbeeifoundthatthe use of thecmtainerwithaglobuleofmercuryinsteadoiiheprevimlslynsedmassorballsintoasulxtaniialdegrce.

Drivingmeanshavingaslipdrivingconneciiontothegyromborareprovdedordrivingthe trame to rotate the mercurycmtainercared thereby, together lithhraking means for retard-Ving'thezooizationoi?1thei1'arneancilnercurycontainertoproduceslipplngaciioninthedvebetweeniheirameandthegyrorotoathebycausingiherotamoftheframeandmercury container ataspeedtiailysmaller thanthespeedofrotaiitmoitbegymrotor. y'.l'he brakingmeansameinthei'ormoan'tdevicecaredbytheirameandcooperating-with awaliofthegymcasing.

Asiongasthemhoraxisranainsinitsnon' mallyvernealpudmmeramerommnssubstaniiallyciantmeedwhlchaspointedoutaboveiscmsidcrahlysnallerthanthespeed' of rotation of the'gyrorotor.' For example,` the trarnemayrotai'aeataqacetioionlyafewdosaashroughtbaektoacstlnispeed.Refeningnowtomlandofthednwingforamoredetaileddescriptimthepresmtinvention l.is shown as colnpring a inciudmgarotilmountedwithinacasmg IIiorapinningaboutanormallyvertlcaiaxis. me

rotor 'Ilhasashattilaecln'edtheretooronnedintegrailyierewmonemdoshaftllbeing iomnalledin-abearingatthebottomofthecasing Ilwhiletheupperendotheshaftisiournalledinasimilarbearingmotshown) in theupperpartofthe'caslng. l

'Ihecasing l|,inturn,ismountedina0ardan agimbalringllinwhich thecasingiiispivoted for angularmovement`aboutahorizlolltalaxisiol'medllythetrunnions Il, II, the gimbal ringIl; in turn,`being pivoted for angular movement about a secondhorizontal axis perpendicular-to the mst formed by trunnions II, Ilwhich are journaiied in a iixed support Il. p

Adrlvingdrum Ilismolmtedupontheupper portion of shaft I2 torotatetherewith co-axially with the rotor." in aimanner similar to thatdisclosed in the aforementioned patent to Robert Alkan, 2,159,118.Mounted co-axially with the driving drum Il for rotation about the rotorspin axisisaframe Ilwhichisjournaliedonthe upper end of the shaft' I2beneath the drum Il bybailbearingsllseatedinaninnerballrace I2 and anouter ball race 22 formed integrally with the frame II.

Aslipdriveisprovidedforrotatinl;theirame i! aboutshaft i2 at a speedsubstantially smaller 5 vthanishespeeliofshaft izanditsrotor Il. The

slip drive comprises a. friction member or shoe 23can'iedbyanarmllpivotedatonthe frame I8. The friction shoe 23 cooperateswithamctionbandorcollarzisecuredtothepepheryofthedruml8,andtheshoe2lisurgedinto Irictional driving engagement with the collari byarm 2l withtheaidoiaspngll having one end thereof connected to arm 2l adjacent thepivot andthe other end -con- 15 nectedtoanadjustablescrewzl'threadedina.

post 29 can'iedbytheframe i8. Pressureof shoe 23 upon collar 2i isdetermined by tensioning of spring 2l by adjustment of screw 2l. Byvirtue Aof the connection of arm 1I with frame I! together with theictlonal engagement of shoe lwiththefrictioneollarzlonihedrivingdnnnlailtheirarne llisrotatedbydrum i8 aboutshaftiIandthegyror-otorspinaxisinvewofthe ball bearing connection 2l, 2l,2.2.'

25 'me 'speed of miauw of mme ls'musn be substantially smaller than thatof the mtorand likewise su independent of any variatlonsintherotorspeed.Braking and regulating means are provided for this pumoae andconsostitutearollerliom-nalledbymeansofashaftiiinanannilivoiedandsecuredtoirameil at. Roilerllengagesthewalllofadrum:Sformingpartofthecasingiitorolltherealong when in engagement therewith'while l5h-ameiisrotated. Securedtoorormedintegrallywith the shaft 3l ofroller 3l to rotateiiaerewithis an escapemmtvstarwheel 'which cooperatwith a forked anchor 3l pivoted at 38 .onthearmllIhisstructureprovidessn 0 escapelnent device having a non-isochronous""retumthenequencyorperhdoioscillationoiiheanchorldependingonthespeedofrotation ofrollerlandstarwheeltothusprovidea smailxetardingorceonmllerll duringrela--istivelysmalispeedsandagrelterretardingiorceduringncreasedspeedtomaintamthehame rotation at a substantially constantspeed.

ThepvotaiaxisofanchorllisanangedVparallelto'ti'legyrorotorspiliaxisanditisatl- 515 vantageous to locatethe center of gravity of the anchor 31 away :from its pivotal/axis 3| tothereby formablockorientedinazlmuthinsuch amannerthattheperlodorirequmcyofoscillationof the anchor, and, therefore, the speedofrotationofthetrame I!shallbeaileclaelinotl only by variations inthedrivng torque due to increasedspeedofrotatimofrotor Il andshaft l2but also by acceleration forces inpreed Also forming-Ya part of theabove braking and regulating mechanism is a centrifugal weight t securedto the movable end ot pivoted arm at the point where friction shoe 23 islikewise attached.

e5 mwlmmenovlfaturebrme forces for returning spin axis tovertical in theevent the spin axis departs trom vertical for any reason. The capsule Iltogether with -tlie mercury II comprise Va'relatively heavy ight.Camille Il is adjustably Secund to the 2| rigidly securedto the upperportion of shaft I5A frame Il by means of a bracket l2 and 'set screw 43which passes through the yslot 44 of the bracket and secures the latterand the capsule for rotation with frame I 9.

In operation, when the gyro rotor I0 is rotated with its shaft I2, thedriving drum I8 carried by the shaft drives the frame I9 throughfriction members 23 and 26 thereby rotating the frame about the shaft I2together with weight 39, ca psule 40 and mercury 4I, and roller 30.Rotation of roller 30 along wall 34 is regulated and limited by theaction of anchor 31 which in turn depends upon the speed of rotation offrame I9.

Should the speed of rotation of the frame I9 increase due to either anincreasey in the speed of rotation of rotor I or due to other causes,the rotation of roller 30 along wall 34 is braked due to the increasedfrequency of oscillation of the anchor 3l upon txhe starwheel 36,thereby retarding the ,rotationfof frame I9 and capsule 40, the latterof which, together with the mercury, comprises the relatively heavyweight. At the same time, centrifugalforces developed due to rotation offrame I9 act on weight 39 to .reduce the pressure of friction shoe 23 oncollar 26 of driving drum I8, thereby reducing lthe driving couple uponthe rotating frame I9.

With a decrease in the speed of rotation of the frame I9, the anchor 31oscillates less frequently because -the speed of rotation of roller 30is decreased thereby reducing the braking action produced by anchor 3:1upon roller 30 and the centrifugal forces acting upon weight 39 beingdecreased permit an increase in friction between friction shoe 23 anddrum I8 thusincreasing driving action on the frame I9. As a result,frame I9 and capsule-49 tend to take up a speed of rotation such thatthe braking action exerted by anchor 31 and the increased driving actionof brake shoe 23 and .friction band 26 balance each other, therebybringing about a' constant speed of rotation of the frame I9 and capsule49, which is entirely independent of the gyro rotor speed and which canbe brought down to a few dozens of revolutions per minute even thoughthe rotor I0 and driving drum I8 rotate at several thousand revolutionsper minute.

Assuming no'w that an acceleration force acts ln the direction of thecentral arrow 45 shown in Figure 1 and-in the plane of the paper causinga. departure of the rotor spin axis from the normally vertical position,and the gyro rotor together with frame I 9 and capsule 46 are rotatingclockwise as indicated by arrow 46, the action of the acceleration forceexerted on the capsule 4U will tend to increase its speed of rotation atthe instant the capsule is in the position shownin Figure 1 and at thesame time will tend to urge the mercury to roll against the rounded orleading end of the capsule thereby tending to cause a further increasein the speed of rotation of the capsule unti i ie moment that thecapsule 40 reaches a pos-itin diametrically opposite to that shown inFigur i l, at which time the mercury rolls from the ieading end to thetrailing end of the capsule thereby providing a momentary stopping ofthe frame rotation. Due to this momentary stopping of the capsule andmercury in the position diametrically opposite to that shown in Figure1, moments are developed by the mercury capsule due to gravitationalpull thereon in the direction toward the plane of the paper and aboutthe trurnions I 6, I6 thereby causing the spin axis of the rotor toprecess aboutv the trunnions I5, VI back to its normally verticalposition.

Since the speed of rotation of the frame I9 and the capsule 49 togetherwith the mercury therein is entirely independent of any variations ingyro rotor speed and, therefore, substantially 5 constant when the gyrorotor spin axis is in a true vertical position, the only variation inthe speed of rotation of frame I9 and capsule 40 together with itsmercury is that caused by accelerations acting on the mercury capsuleand 10 that due to deviation of the spin axis from the true vertical.For this reason, even a small acceleration is sufficient to make thetime during which the'mercurycapsule travels around one half of thecircumference to materially differ from the time required for it totravel around the other half of the circumference. variation manifestsitself by a tendency of the gyro to erect its spin axis in the directionof the acceleration and vby a direct linear precessional movement andnot by-a spiral precessional move- Iment.

An acceleration component acting in the direction of the arrow 45, shownin Figure 1, also manifests itself by acting on the friction shoe 23 5to increase the driving torque of drum I 8 onthe frame I9 and themercury capsule, thereby increasing the rotational speed of the mercurycapsule during the downward half turn, as seen in Figure 1, and duringthe upward half turn 3o the acceleration force acts on the brake shoe 23l and the mercury capsule in the reverse direction so as to urge brakeshoe 23 away from the brake lining to decrease the frictional engagementtherebetween with a consequent slowing down of the mercury capsule. K Byadjusting the position of the mercury capsule 40 by set screw 43 it ispossible to regulate, vas desired,.the phase of the variations of thespeed of capsule 4|! in relation to the angular 40 position thereof.

Freedom of `motion "of the liquid within the capsule 40 is at all timeshighly desirable, and

this is accomplished by choice cf suitable liquid,

which in the present instance has been described as mercury 4I, but itis to be understood that other liquid may be used as well. Likewise, the

capsule maybe formed of glass or other suitable material having itssurface properly prepared so as to eliminate the presence of anycontaminat-` ingsubstances.

The foregoing operation of the erecting mechanisvm has been describedonly -in .connection with acceleration forces acting to disturb therotor spin axis. However, tilting of the rotor spin axis due to bearingfriction or causes other than acceleration forces results in the sameoperation of the. erecting mechanism with the exception that in place ofthe acceleration forces, a gravitational pull is exerted upon capsule 40to speed up its movement over one-half of the circumference of wall 34,dependingupon th'e direction of tilt, and to slow up the capsule duringits upward movement. At the time that upward move- Ament beginsmomentary stopping of capsule 40 and the mercury ball, due to thegravitational pull which is in the opposite directionV at this point,results to create moments about either axis I5 or I6, again dependingupon the direction of tilt, to cause the rotor to precess into itsnormally vertical position,

` From the foregoing, it will be apparent to those skilled in the artthat a novel gyro-vertical has been provided having novel erecting meansfor maintaining the gyro spin axis in a true vertical position at al1times without th'e use of re- Sllch a about said spin axis, and a withinsaid container and having freedom of movement therein so as to berelatively displaced within said container upon deviation ot'said spinAlthough but one embodiment of the invention has been illustrated 'anddescribed, various changes and-modications in the form and relativearrangement of parts, which will now appear to those skilled in the art,may be made without axis to actuate the regulating means to vary thespeed of rotation o! said frame whereby erecting forces are developed,on4 the gyroscope to return said rotor spin'axis to its normallyverdeparting from the scope of the invention. Vl'teference is thereforeto be had to' the appended claims for a deiinition oi the limitsoi theinvention.

What is claimed is:

l. In a gyro vertical, the combination of a gyroscope comprising a rotormounted for spinning about a nrmally vertical axis, a casing mountingsaid rotor for angular movement about two mutually perpendicularhorizontal axes at right angles to the spin axis, a rotatable frame,means mounting vsaid frame for rotation about the spin axis of saidrotor, means drivably connecting saidgframe with said rotor whereby saidframe is rotated at a speed substantially less than the aspeed ofsaidrotor, regulating means comprising braking means carried by saidframe and in engagement with said casing for maintaining the speed offrame rotation substantially constant while the spin axis of said rotoris in itsnormally vertical position and adapted to vary the speed oiframe rotation when the spin axis of said rotor deviates from saidvertical position, a hollow container mounted on said frame for rotationtherewith about said spin axis, and a mass located within said containerhaving freedom of movement therein so as to be relatively displacedwithin said container upon.

deviation of said spin axis to actuate the regulating means to vary thespeed of rotation of said frame whereby erecting forces are developed on`the gyroscope to return said rotor spin axis to its normally verticalposition.

2. In'a gyro vertical, the combination of a gyroscope comprising a rotormounted for spinning about a normally vertical axis, fa casing mountingsaid rotor for angular movement about two mutually perpendicularhorizontal axes at right angles to the spin axis, a rotatable frame,means mounting said frame for rotation about the spin axis of saidrotor, means drivably connecting said frame with said-rotor whereby saidframe is rotated at a speed substantially les's than the speed of saidrotor. regulating means comprising an escapement mechanism carried bysaid frame and in engagement with said casing for maintaining the speedof frame rotation substantially constant'c while the Spin axis of saidrotor is in its normally vertical position and adapted to vary the speedof frame rotation when the spin axis of said rotor deviates from saidvertical position, a sealed hollow container mounted on said frame forrotation therewith tical position.

3.. In a gyro vertical, the combination of a gyroscope comprising arotor mounted for. spinning about a normally vertical-axis. a easingmounting said rotor for angular movement-about two mutuallyperpendicular horizontal axes at right angles to the-spin axis, arotatable frame, means mounting said trame tor'rotation about an axisco-axial with `said rotorspin axis, means drivably connecting, said'frame with said rotor Vwhereby said frame is rotated at a speedsubstantially less than the speed of said rotor, regulating meansconnected to said trame for main- 'taining the speed of frame rotationsubstantially constant while the spin axis oi.' said rotor is in itsn'ormally vertical position and adapted to vary the speed of framerotationwhen the spin axis of said rotor deviates from said verticalposition,

a capsule mounted 'on said trame and rotatable therewith about said spinaxis, and a globule 'ot mercury located within said capsule for rollingmovement thereiny so as to be relatively displaced within said capsuleupon deviation of said spin axis to actuate the regulating means to varythe speed of rotation of said frame whereby erecting forces aredeveloped on the gyroscope to return said rotor spin axis to itsnormally vertical position.

4. In a gyro vertical, the combination of a gyroscope comprising sarotor mounted for spinning about a normally vertical axis. acaslngmounting said rotor for angular movement about two mutuallyperpendicular horizontal axes at right angles tothe spin axis, asubstantially circular rotatable frame, means mounting said frame forrotation about the spin axis of said rotor, a slipconnection from Isaidrotor to said frame for rotatingsaid frame at a speed substantially lessthan the speed of said rotor, regulating means connected' to said framefor maintaining the speed of frame rotation substantially constant whilethe spin axis of said rotor is in its normally vertical position andadapted to vary the speed of frame rotation when the spin axis of saidrotor deviates from said vertical position, a capsule secured to theouter periphery of said frame for rotation therewith about said spinaxis, and a 'n globule of mercury disposed within said capsule forrolling movement therein so as to be relatively displaced within saidcapsule upon deviation of said spin axis to actuate the regulating meansto vary the speed of rotation of said frame whereby erecting forces aredeveloped on the gyroscope to return said yrotor spin axis to itsnormally vertical position.

' 'HUGH G. HAMILTON.

uid mass located p

